Coming from me, this may be a "dumb" question, but not a stoopid one. What are the structural differences between a violin and a viola?? I know that:
Viola is a fifth lower. Tunes A E G C--violin tunes E A D G
Violas are bigger, usually 16" or 15.25"
Standard 4/4 violin is 14" BUT so is a 3/4 size viola.
I had a girl over today who swears that her 14" instrument is a 3/4 viola. I don't think so. Felt like a violin, and I KNOW it had 4/4 violin strings on it, so that is how I tuned it.

She couldn't play it because she was used to viola tuning/alto clef.
SOooo,

Other than tuning/size, what are the differences?? Doesn't a viola have thicker ribs and more arch in the belly? If we decide to put 3/4 size viola strings on what is essentially a 4/4 violin, what might happen?

Problem is, we want to play together but I read treble clef, she reads alto...........small problem. She promised to work on treble, I promised to work on alto, but in the meantime.........HELP!